Answer:
20, 20, 15, 20, 10, and 5 iterations respectively
Step-by-step explanation:
The loop "for (int i = 0; i < 20; i+ +)" starts at i=0 and increases the counter i by 1 at the end of each iteration. The counter must be less than 20, so the values of i in the loop are 0,1,2,3,...,19. These are 20 values, and thus the code iterated 20 times.
The loop "for (int i = 0; i < 20; i+ +)" starts at i=1 and increases the counter i by 1 at the end of each iteration. The counter can't exceed 20, so the values of i in the loop are 1,2,3,4,...,20. These are 20 values, and thus the code iterated 20 times.
Similarly, in "for (int i = 5; i < 20; i+ +)" i takes the 15 values are 5,6,7,...,19. Hence, the code iterated 15 times.
The loop "for (int i = 20; i > 0; i- -)" starts at i=20 and decreases the counter i by 1 at the end of each iteration, so the values of i in the loop are 20,19,18,...,1. These are 20 values, then we have 20 iterations.
The loop "for (int i = 1; i < 20; i = i + 2)" starts at i=1 and increases the counter i by 2 at the end of each iteration. The values of i in the loop are 1,3,5,7,...,19. These are 10 values, and thus the code iterated 10 times.
The loop "for (int i = 0; i < 20; i+ +)" starts at i=1 and multiplies the counter i by 2 at the end of each iteration, so the values of i in the loop are 1,2,4,8,16. Then we have 5 iterations.
